Boiler net ratings

DanHolohan

<a href="http://www.heatinghelp.com/newsletter.cfm?Id=64">Boiler Ratings</a>

Chuck_7

Oil hot water boiler size

I think I understand net ratings. I usually do not think about them. I typically work with commercial systems which have pipe insulation. For that matter usually two slightly over sized boilers are used.
I am looking at a new single family residence with radiant heat which needs an oil fired boiler. The house load is about 115MBH. Should I size that boiler based on the gross output or should I count on some losses?